The invention relates to an on-line measurement system for measuring various properties of a product and more particularly to an on-line measurement system for in situ measurement of various properties of a product being flowing through a conduit.
In the manufacturing of some materials, for example, polymeric materials, the product undergoes several manufacturing processes before the final product is created. These processes can be performed in one processing area or at several processing areas. In either case, the product is transported from process to process, or the product is transported to a finishing area. In addition, at the final processing area the product can be formed into various shapes and sizes. Typically, the movement and forming of the product is accomplished by extruding the material through a conduit. Since the conduit is generally chosen for their high strength and low cost and such materials are typically opaque, the conduits are also opaque.
Many processes, especially the finishing process, desire to identify or measure the color and other properties of the product. Color identification and measurement of other properties are desired for, among other things, determining the state of the process, determining the aesthetic value of the product, determining the quality of the product and sorting the product. However, opaque conduits make identification of the color and other properties of the product difficult. In one example, color of the product is identified and measured by directing a portion of the product to a bypass section in the conduit such as a main extruder. A sample of the product is directed through the bypass section where an operator takes a portion of the sampled product. The operator manually supplies the portion of the sampled product to a spectrophotometer where the color is measured. This process of color measurement and identification is time consuming and, therefore, increases the manufacturing time of the product which in turn increase the costs associated with manufacturing.
Therefore, there is a desire for an optical sensor that provides in situ measurement of color and other properties a product as the product flows through a conduit during manufacturing.
In one exemplary embodiment, an on-line sensor is provided that supplies light to a spectrophotometer for in situ measurement of properties of a product while the product is being extruded from conduit that has a bypass section. The on-line sensor includes a transparent member that comprises a first cylindrical section having a first diameter that is connected to the bypass section. A portion of the product flows through the first cylindrical section. A second cylindrical section is also provided that has a second diameter concentric to the first diameter, and the second diameter is greater than the first diameter. The on-line sensor also includes an opaque casing that houses the transparent member and has a first and a second receptacle. A light source is connected to the first receptacle of the opaque casing and provides light to the transparent member inside the opaque casing. A light receiver is connected to the spectrophotometer and the second receptacle of the opaque casing. Also, the light receiver can be positioned at a distant location from the on-line sensor. The light receiver captures light from the light source in the transparent member that is affected by the portion of the product in the first cylindrical section. The captured light is supplied to at least the spectrophotometer for measuring the properties of the portion of product in the first cylindrical section of the transparent member.